How to Reduce Risks of Bad Air Quality

01Air quality differs from place to place and day to day.

02But about 99% of the world's population breathes air at some point that does not meet pollution guidelines set by the World Health Organization, WHO.

03Different forms of air pollution kill about 7 million people each year, the UN Health Agency estimates.

04But health experts say there are some actions individuals can take to protect themselves, even in the world's most polluted cities.

05The first step is to start with the understanding that air is not only polluted when it looks smoky or smoggy, said Tanushri Ganguly.

06She is an air quality expert with the Energy Policy Institute of Chicago's India program.

07Blue skies can't guarantee you clean air, Ganguly told the Associated Press.

08Air pollutants often come from people burning things.

09Examples include fuels, as well as clearing operations involving crops or trees.

10Pollutants can also be released from wildfires.

11Among the most dangerous particles we can breathe in are called particulate matter.

12The smallest of these are known as PM2.5.

13This is because they are less than 2.5 microns in diameter.

14These particles can travel deep inside human lungs and are mostly created by burning fuels.

15Larger particles, known as PM10, are linked to agriculture, roadways, mining, or wind-blown dust.

16Other dangerous pollutants include gases like nitrogen dioxide or sulfur dioxide, which are also produced from burning fuels.

17This information comes from Anumita Roychaudhry, an air pollution expert at the Center for Science and Environment in New Delhi.

18The American-based Health Effects Institute says air pollution is the second-largest risk factor for early death worldwide, behind blood pressure.

19Short-term exposure can cause asthma attacks and increase the risk of heart attacks and stroke, especially in older people and those with existing medical problems.

20Long-term exposure can cause serious heart and lung problems that can lead to death.

21A recent study by the UN Children's Agency, UNICEF, found that more than 500 million children in East Asia and Pacific countries breathe unhealthy air.

22The pollution is linked to the deaths of 100 children under age 5 every day.

23June Kunugi, UNICEF's regional director for East Asia, said the polluted air limits growth, harms lungs, and affects thinking abilities.

24Every breath matters, but for too many children, every breath can bring harm, she said.

25Over 6,000 cities in 117 countries now record and follow air quality levels.

26Many mobile apps include air quality information as well, but it can be difficult to know how bad the air is by looking at these numbers.

27To help people better understand air quality levels, many countries have established an Air Quality Index, or AQI.

28Larger numbers on this index mean worse air.

29Different countries have different air quality standards.

30For example, India's daily PM2.5 limit is more than 1.5 times higher than in Thailand, and 4 times higher than WHO standards.

31For individuals, experts say the goal should be to limit exposure when air quality is bad by staying indoors or wearing a mask.

32This is not always possible, though.

33Danny Jaram is with the World Resources Institute.

34He told the AP there are many people who live or work outside and can't really afford to stay indoors.

35People also need to watch indoor air pollution that can be caused by common household activities like cooking or burning incense.

36While air purifiers can help reduce indoor air pollution, experts say they do have limitations.

37The devices work by pulling air from a room and then pushing it through a filter that traps pollutants.

38The filtered air is then sent back into the room.

39Air purifiers work best when used in small spaces and when people are nearby.

40This is because they can only clean a certain amount of air, said Raja Sekar Balasubramanian of the National University of Singapore.

41He added, If we have a tiny air purifier in a large room, it won't be effective.

42I'm John Russell.

43And I'm Katie Weaver.